


Exaptation

by OneOfThoseThings



Series: Interspecies Compatibility [9]
Category: Doctor Who (2005)
Genre: Alien/Human Relationships, Angst and Fluff and Smut, F/M, Interspecies Relationship(s), Morning After, Porn With Plot, Straight up sex, no beta we die like men
Language: English
Status: Completed
Published: 2020-03-10
Updated: 2020-03-10
Packaged: 2021-03-01 01:01:51
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 3,279
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23086705
Author URL: https://archiveofourown.org/users/OneOfThoseThings/pseuds/OneOfThoseThings
Summary: The morning (or TARDIS equivalent) after, the Doctor and Donna proceed with caution. Well... one proceeds with caution. The other wakes up ready to go again. Some convincing is needed.(An entirely optional interlude for those of us who like a little morning after action and don't mind a disruption in plot.)
Relationships: Tenth Doctor/Donna Noble
Series: Interspecies Compatibility [9]
Series URL: https://archiveofourown.org/series/1637608
Comments: 10
Kudos: 110





	1. Part the First

**Author's Note:**

> Exaptation (ala Wikipedia): A shift in the function of a trait during evolution. For example, a trait can evolve because it served one particular function, but subsequently it may come to serve another... Bird feathers are a classic example: initially they may have evolved for temperature regulation, but later were adapted for flight.

The Doctor rarely slept, so he was understandably confused when he woke up without remembering falling asleep. It didn’t help that he woke up in motion, falling off the bed in a tangle of violet sheets. 

Donna’s face appeared, looking down at him. “What did you do that for?” she asked.

The Doctor tried and failed to figure out what part of that she felt he’d done on purpose. He tried to sit up, only to find himself tangling further, like a Chinese finger trap. “Donna, what―?“ He was wearing a robe. Why was he wearing a robe? And why was it tied to the sheets??

Donna watched him thrash around for a bit and then reached down and freed him with two tugs. “Not exactly a fairy tale princess waker upper are you?” 

He sat up, bracing his back against the bed, trying to get himself back online. “I’m in your room,” he said, craning his neck around to look at her over the edge of the mattress. “Why am I―” Several memories slotted into place, making the whole scene make much more sense.

It also, incidentally, made it a bit awkward for him to be on the floor. “…Ah.” 

“Ah,” she echoed, looking him over like she couldn’t quite remember what he looked like.

Donna shifted closer and he watched in his peripheral vision, trying to assess her mood without looking like he was trying to assess her mood. 

She’d never been affected by the telepathic synthesis before; it hadn’t even registered to her. But that last time… he suspected something had made it through her shuttered senses. He wasn’t quite sure how to ask what. 

She stroked one hand through his hair and he shivered. Her fingers twitched away, hovering just close enough for him to still feel the warmth. 

“All right?” she asked.

He nodded. “Just a bit, er, sensitized still.” 

“Oh?” she said, sounding intrigued. Her fingertips traced the tendon in his neck down to his collarbone and then followed the hem of his robe. “How sensitized?” 

He tried to subtly turn his head far enough to get a clearer look at her expression. She didn’t look scared or even skittish. He wondered if he’d had some sort of fever dream, imagining her reaction earlier. 

She quirked her eyebrows and he realized she’d asked him a question. “Er. Somewhat. Took sixteen hours to wear off the last time; still have about six to go. It’s not a problem. I don’t expect―“ She slid her fingers under the edge of his collar, and his voice jumped up a bit in surprise. 

“Do you think you could… make do… without the mental bit?” she asked, in an oddly neutral tone. 

His neck strained at the sharp turn. “You don’t need to offer― I’m perfectly fine.”

“Ah. Right. No, you wouldn’t want to―“ Her hand withdrew and she sat up, shuffling to the other side of the bed. “I’ll just pop to the loo. Human things, you know.” 

She disappeared into the ensuite before he could think of anything to say. 

He immediately set to detangling himself, struggling upright and adjusting the completely impractical robe that had to be detangled separately. Once that was accomplished he stood there, not quite sure what to do with himself. 

Stay? Leave? Make the bed? Try to disguise himself as a bizarrely large pillow?

Donna reappeared before he could decide. 

“Oh, good,” she said, “Legs still working then?” 

He automatically tried to put his hands in his pockets, realized that wasn’t an option, and awkwardly crossed his arms. “Yes, yes. Just a bit disoriented, as I mentioned. Hardly ever sleep that much, me.” He looked her over, but she seemed fine. “…Are you all right?” he blurted out, interrupting himself. 

“ _You’re_ asking _me_ that?” Donna looked genuinely baffled. 

He took a quick mental assessment to make sure he wasn’t missing any limbs he just hadn’t noticed yet. Nothing stood out. “Er,” he said. “It’s just that you seemed a bit…” Something in her expression shuttered and he found himself unable to complete that sentence. 

He wasn’t sure what he was expecting, but he was entirely surprised when she pulled him into a hug.

He hugged her back, trying not to overthink it. She certainly seemed fine. A bit warmer than usual, but that was probably his lingering sensitivity. She wasn’t stiff or trembling. She was actually quite soft, now that he was noticing. He rubbed his cheek against her hair, absently. 

Donna chuffed, puffing air into his collar. “You sure you don’t want to give it another go? Feels like you might.” 

He blinked, trying to figure out what she could possibly mean by that. “What?” 

She shifted, arching her back just slightly and he suddenly realized he’d _felt_ that in a way he wasn’t used to feeling, well, anything. “Oh… _Oh_!” He jerked himself back. “Ah! Sorry! Must still be― Sorry, sorry!” 

Donna sighed, looking strangely disappointed. 

Quite suddenly, he remembered that _she_ actually liked this. “Er,” he said, intelligently, “Would _you_ like to, uh… 'give it another go?'”

She looked him up and down. “Human-style works for you right now… right?” 

He tried to subtly straighten himself out. “Yes, but I don’t _need_ ―“

She stepped closer and he shut up, which was convenient because in the next move she pulled him down by the collar and kissed him. She tasted minty again, but he was more distracted by how her arms fit over his shoulders, one wrist rubbing against the back of his neck. 

His hands were already on her waist, seeking the heat radiating from under her robe. She pressed in closer, warm and soft and he was much more interested in the points of contact than usual. 

Donna leaned back and he followed until she stopped him with a hand on his chest, puffing a laugh into his mouth. “All right, then?” 

He nodded, reconnecting and shifting his grip down to her hips.

She worked the hand on his chest under the robe, and he was very interested in where she was going with that. She chuckled at the sound he made, but dropped her other hand to the sash, working it open. 

He pulled hers loose with two tugs and started to move it down her shoulders. She started to shake it off, and he moved his hands to her face to adjust the angle without getting in the way. 

Donna recoiled violently, breaking the kiss and stumbling back like he’d slapped her. 

“Donna?” he asked, fingers tingling.

“Can we not do the mental part?” she asked, ducking so her fringe obscured her expression. 

“I wasn’t―“ He put his hands down. “I wouldn’t without asking.” Not that he usually needed to. She always seemed to offer.

He flexed his hands awkwardly at his sides, trying to figure out how to ask a question he wasn’t sure he wanted to hear the answer to. 

Donna crossed her arms, pulling her robe tighter. A protective, defensive gesture. “Could we just do the normal― the human bits?”

“We don’t have to do _anything_ ,” he reminded her, “You don’t need to―“

“No, I _want_ to―” She gave him a strange, desperate look. “Can’t we just…” Her shoulders tightened, twitching higher. 

“We can do or not do whatever you want,” he said, very slowly. “Whatever you’re comfortable with,” he added, keeping his tone carefully neutral. 

She looked his face over, assessing. “Would that be― It seems like you could still enjoy― What do _you_ want?” 

He wanted to be some better version of himself that could tell what was actually wrong with her. But that seemed unlikely to be something she could give him at the moment. 

“Whatever you’re comfortable with,” he repeated, as cowardly as ever. 


	2. Part the Second (NSFW)

The Doctor wasn’t sure what to make of Donna’s behavior. He suspected he should ask her (again) or at least stop kissing her in case she’d just tell him herself, but it was getting harder and harder to remember why with a dose of human urges still simmering in the back of his mind. 

Donna’s preternaturally hot hands were very distracting, and she certainly seemed to be enjoying touching every inch of skin she could get her hands on. In three quick twists, she had his robe open and off. 

“You’ll like this,” she said, “Let me show you.” 

Having little-to-no experience acting as “the responsible one,” the Doctor wasn’t sure what he should be doing, but he was fairly certain he wasn’t doing it correctly. He figured that was as much her fault as his― if anyone should know that he couldn’t handle being the responsible one, it was Donna. And she’d never seemed to care before.

Not that she seemed to care now. She seemed much more interested in cataloguing every reaction she could wring out of him with a clever application of touch and tongue. 

With a mental shrug, he set any higher concerns aside for some future, more focused version of himself to deal with. Humans liked this sort of thing, and Donna certainly seemed to be enjoying herself. She could be trusted to keep her own boundaries. 

She mouthed her way down his neck, across his collarbone and down to the top of his right pectoral. One hand felt its way down his vertebrae while a leg worked its way in-between his, rubbing the soft skin of her belly against him just so. 

He made approbative noises in the back of his throat, stroking his own way over whatever parts of her he could reach. He hooked one foot behind hers and rocked forward with a bit too much force, lifting her up onto her toes. 

“When you turn it on, you really turn it on, don’t you?” Donna said, sounding a bit impressed.

“Your one-track mind is making more and more sense,” he replied, having a little more trouble with the consonants with the increased air intake. 

The backs of his knees hit the bed and Donna was already clamoring on top of him by his second bounce. There was an awkward tangle of limbs as he pulled himself the rest of the way on and she thoroughly impeded his efforts. Her knee clipped his thigh and she slipped a bit, catching her weight on her left hand which happened to be braced on his sternum, knocking the wind out of him. It was forgotten in the next moment as she regained her balance and moved one hand to his lower abdomen with a much lighter, more purposeful application of pressure. 

She chuckled, low and breathily, “Think you can keep it together if I show you something you’ll really like?” 

“What?” he gasped, trying to focus. “What do you―?“ 

She gave him a strange, slow smile that made his stomach clench. “Let’s find out.” She ducked her head, shifted lower, and swiped her searing tongue from root to tip. 

His hips came off the mattress hard enough to wrench his back, and Donna had to pin him down with both hands, bracing one forearm across his lower abdomen. “Now, now,” she said, puffing air over burning skin, “If you do _that_ , I can’t do _this_ ,” and she ducked her head again, taking him into her scalding mouth. 

Her forearm dug into his pelvis, keeping him from bucking, and her tongue swiveled around the head, whiting out his receptors. He reached for her automatically and suddenly she was gone, flinching back. 

“Just the human bits, remember?” she said, and he stared, panting, trying to make the words make sense. 

She was looking at his hands, still raised.

He forced them back down. “I wasn’t―“ He swallowed, trying to get his thoughts back in order. “I just wanted… to… hold…” He gripped the sheets, willing blood back into his brain. 

Donna gave him a strangely sympathetic look and moved back into reach. “Come here,” she said, wrapping her arms under him and slotting herself against him. It was warm and soft and when he tentatively put his arms around her she just held him closer.

The TARDIS flickered through images of infant marmosets clinging to adults, or whatever warm substitute they were presented with. 

“Ignoring that,” Donna grumbled into his shoulder. She wrapped her arms somehow tighter still, and then shifted her lower half in a slow figure eight, assessing. 

He groaned, deep and grumbling, and she shifted a little more purposefully, somehow pressing the softest skin against him so deliciously. His groan took on a bit of a whimpering quality and she laughed, puffing air against his neck. “Have you always been this easy? Or is this a new development?”

He choked on a clever reply when she sat up and back, pressing warm and wet just where he wanted her. 

She chuffed and adjusted her position, lifting up and then sinking down.

The Doctor let out an entirely undignified sound, fingers digging into the soft flesh at her hips hard enough to bruise. Donna didn’t seem to mind. In fact, she made a similarly undignified sound as she adjusted the angle. 

They worked out a stuttering, perfectly imperfect rhythm in which he rose up to meet each downward stroke. He braced his feet against the mattress, arching his lower half off the bed entirely, and Donna took him deeper still with nearly her full weight. 

He bucked again and she fell forward, panting against his neck and jaw. She rocked in harder, pressing herself against his pubic bone on every stroke. 

An overwhelming urgency built up in his chest, rising in his throat and knotting in his abdomen. “Donna,” he gasped, like he was drowning. His fingers itched to reach for her contact points, but he dug them into her sides instead.

“Almost,” she said, breath fogging his skin. “Just a little―“ He ripped one hand away from her hip, seeking out the bundle of nerves pressed between them and she cried out, trying to arch in and away simultaneously. 

He circled his thumb, and on the second pass she seized up, clenching so hard it should have hurt, but instead it just uncorked whatever was building inside, sending him unravelling. He bucked wildly, and she rocked him in deeper and deeper, until he lost his purchase and just let the waves crash in. 


	3. Part the Third

Donna collapsed next to the Doctor, chest heaving, and he had an uncharacteristically sharp moment of deja vu. He rolled his head to look at her, but she rolled in at the same time, wrapping her arms around him and burying her face in his neck. 

He brought his own arms up automatically and she didn’t feel tense or stressed. Quite the opposite. He was a little surprised she could grip anything when she seemed to have gone boneless. 

For several minutes they just lay there, getting their breathing under control. He still more aware of physical sensations than he might otherwise be, but it wasn’t bad. Even damp and a bit sticky, Donna was still quite soft and nice to hold. After a few minutes more though, she started to feel a bit heavier. 

“Donna?” he started, not quite sure what he was going to ask, but pretty sure he should ask something.

“J’st’a min’,” she mumbled, breathing a bit too deeply. With a low sigh, her grip relaxed and she clearly dropped off to sleep.

He blinked at the crown of her head, wedged under his cheek. 

The TARDIS hummed, trying to work out what he was looking for, plucking at threads of Donna’s dreams, detangling whatever might keep her from deeper sleep. 

The Doctor tried to explain, realized he didn’t actually have anything like an explanation, and quietly left the TARDIS to her mental grooming. 

He didn’t object when she included him in her ministrations, letting her card through the superficial layer of his awareness, smoothing stray worries as she went.

He dropped into something between a light doze and a meditative state, trying very hard not to think about Donna flinching away every time his hands came anywhere near her face. Something had definitely slipped through the last time they’d connected and whatever limited senses she had seemed to have been overloaded. 

Well…He could only hope _that_ was the issue. He found it highly unlikely that a human could make it through his mental shielding, but he had to admit Donna had a uniquely reliable way of proving him wrong. And he shuddered to think of what she might find in him. Her empathy for broken, unloved things surely had a limit, and he didn’t need to actively seek it out. 

She shifted in her sleep, burrowing deeper until every breath she took tickled the hair behind his ear and a she started a light, wheezing snore directly into that ear. 

He shifted around and she pulled the arm under him back, folding it between them. He stilled, but the other arm didn’t move, still curled across his torso and behind his shoulder. 

The TARDIS chittered like he was purposefully making a mess of things she’d just straightened and refocused on her mental preening.

* * *

Eventually, Donna shifted in increasing levels of awareness and he felt her eyelashes flutter against his skin. She went slightly tense, starting to slide the arm under his shoulder back towards herself, but she stopped with her forearm over his right heart, pressing down like she was checking the rhythm. The back of her other hand curled against his chest, just over his left heart and after exactly four heartsbeats, she pulled back, blinking at him. 

The Doctor blinked back at her, not quite sure what to make of any of that. 

“I fell asleep,” Donna said, like he might not have noticed. 

“Yep,” he said, popping the ‘p’ slightly. 

She shifted, realized she had a leg thrown over his, and slowly pulled it back, leaving a damp impression that he tried not to acknowledge. 

“Perhaps a shower,” she suggested, grimacing slightly. 

“A shower,” he repeated, “Good idea.” 

“Then maybe breakfast,” she said, “Or lunch. Or― whatever― Food.” 

He nodded. “Yes. Food. Another good idea.” 

She didn’t move; the pulse in her wrist tapping against his chest. He held very still, trying not to do anything alarming. 

“Right,” she said, finally, “I’ll go first, shall I?” 

“Well,” he said, “I could shower in my room. Save time.”

She nodded, looking around for something and clearly not listening. “Time, yes.”

The headboard panel tipped open and two robes flopped out. 

“Ah,” Donna said, like the room service had just arrived, “Thanks.” She sat up, pulling the robe on. “...Don’t suppose…” 

The panel flipped around again, dropping an orange sports drink onto the pillow. “Perfect! Thanks!” She patted the wall, and unscrewed the bottle, downing half of it in three large gulps. She offered the rest to the Doctor and he took the bottle just to have something to do with his hands. 

It tasted like the color orange laced with electrolytes. “You asked for this?” he grimaced, handing the bottle back. 

Donna shrugged and downed the rest. “I didn’t specify a brand and flavor, but yeah, basically. Gotta stay hydrated, right?” She swiped a hand through her hair, making a face at the texture. 

“Right,” he said, pulling the other robe on― blue this time. 

“Right,” she repeated, scooting off the bed. She hesitated with one foot on the ground and darted forward for a quick kiss before scurrying off to the ensuite. The door closed before he could register much more than a warm impression. 

“Right,” he said, quietly. 

The TARDIS hummed, reminding him that he didn’t actually have to speak out loud to her. 


End file.
